【摘要】：波浪荷載作用下海床土體中會(huì)產(chǎn)生孔隙水壓力。當(dāng)孔隙水壓力累積到一定程度后,海床土體會(huì)出現(xiàn)液化和失穩(wěn)破壞等行為。為更好地開(kāi)發(fā)和利用海洋資源,需要加深波浪荷載下海床動(dòng)力響應(yīng)的研究,從而為近海地基土在動(dòng)荷載下的動(dòng)力特性和液化可能性以及海床與近海結(jié)構(gòu)物地基穩(wěn)定性的評(píng)判提供依據(jù),這具有重要的理論和現(xiàn)實(shí)意義。在前人研究工作的基礎(chǔ)上,本文通過(guò)理論和數(shù)值模擬相結(jié)合的方法對(duì)波浪荷載作用下海床土體的動(dòng)力響應(yīng)、動(dòng)孔隙水壓力的累積和發(fā)展規(guī)律、海床液化規(guī)律及其影響因素等進(jìn)行了一系列研究工作,其主要成果如下：(1)扼要概述國(guó)內(nèi)外關(guān)于波浪荷載作用下海床土體動(dòng)力響應(yīng)相關(guān)的研究成果和研究方法；了解粉土的定義及性質(zhì)、土體液化的形式及其判斷準(zhǔn)則等；(2)首先簡(jiǎn)要介紹了勢(shì)波理論及其求解、線性波的特征和波浪-海床的相互作用；接著扼要介紹了土介質(zhì)中波的概念和特征,并對(duì)孔隙水壓導(dǎo)致海床液化的可能性進(jìn)行分析；(3)采用解析法求解平面應(yīng)變條件下的Biot波動(dòng)方程,結(jié)合邊界條件推導(dǎo)出穩(wěn)態(tài)波浪荷載作用下海床土體的應(yīng)力、變形和孔隙水壓力,并通過(guò)數(shù)值算例分析波浪-海床參數(shù)對(duì)海床地基土動(dòng)力響應(yīng)的影響；(4)采用有限差分Flac3D分析軟件對(duì)波浪荷載作用下海床的動(dòng)力特性進(jìn)行數(shù)值模擬與分析,分析了波浪荷載作用下土體的動(dòng)應(yīng)力-動(dòng)變形特性、總應(yīng)力、孔隙水壓力、有效應(yīng)力的變化規(guī)律,探討了海床土體的液化情況,分析水深、周期、波高對(duì)近海粉土抗液化能力的影響。結(jié)果表明：①粉土海床在波浪荷載作用下孔隙水壓力累積現(xiàn)象比較明顯。孔壓累積引起孔隙水壓力的增大和有效應(yīng)力的減小。當(dāng)有效應(yīng)力減小到零時(shí)土體出現(xiàn)液化現(xiàn)象；②在其他條件相同的情況下,波高越大,累積孔壓越大且液化深度越大；周期越長(zhǎng),波長(zhǎng)、波壓力、波速越大,且液化深度越大。③水深大小影響海床中孔壓的累積并影響液化深度,在同等條件下隨水深增加液化深度先增加后減小。
[Abstract]:The pore water pressure will be produced in the seabed soil under wave load. When pore water pressure accumulates to a certain extent, the behavior of liquefaction and instability occurs. In order to develop and utilize marine resources better, it is necessary to deepen the research on the dynamic response of ocean bed under wave loads. Therefore, it is of great theoretical and practical significance to provide the basis for the evaluation of the dynamic characteristics and liquefaction possibility of the offshore soil under the dynamic load, as well as the stability of the seabed and the offshore structure foundation. On the basis of previous research work, the dynamic response of seabed soil under wave loads and the accumulation and development of dynamic pore water pressure are studied by combining theory with numerical simulation. A series of research work has been done on the law of seabed liquefaction and its influencing factors. The main results are as follows: (1) the research results and research methods related to the dynamic response of the seabed soil under wave loads are summarized briefly at home and abroad; The definition and properties of silt, the form of soil liquefaction and its judgment criteria are understood. (2) the theory of potential wave and its solution, the characteristics of linear wave and the interaction between wave and seabed are introduced briefly. Secondly, the concept and characteristics of wave in soil medium are briefly introduced, and the possibility of liquefaction of seabed caused by pore water pressure is analyzed. (3) the Biot wave equation under plane strain condition is solved by analytical method, and the stress, deformation and pore water pressure of seabed soil under steady wave load are deduced in combination with boundary conditions. The influence of wave-seabed parameters on the dynamic response of seabed soil is analyzed by numerical examples. (4) numerical simulation and analysis of the dynamic characteristics of the seabed under wave load are carried out by using finite difference Flac3D software. The dynamic stress-dynamic deformation characteristics, total stress and pore water pressure of soil under wave load are analyzed. The effect of water depth, period and wave height on the liquefaction resistance of offshore silt is analyzed. The results show that: 1 the accumulation of pore water pressure on silt seabed under wave loads is obvious. Pore pressure accumulation results in the increase of pore water pressure and the decrease of effective stress. When the effective stress is reduced to 00:00, liquefaction occurs in the soil. 2 under the same conditions, the higher the wave height, the greater the accumulated pore pressure and the greater the liquefaction depth. The longer the period, the greater the wave pressure and velocity, and the greater the depth of liquefaction. 3 the depth of water affects the accumulation of pore pressure in the seabed and the depth of liquefaction. Under the same conditions, the depth of liquefaction increases first and then decreases with the increase of water depth.
【學(xué)位授予單位】：浙江工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU435

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 閆澍旺,邱長(zhǎng)林,孫寶倉(cāng),章為民;波浪作用下海底軟粘土力學(xué)性狀的離心模型試驗(yàn)研究[J];水利學(xué)報(bào);1998年09期

，

本文編號(hào)：2329123